National Grid, which operates the UK power network, expects there to be sufficient generation and capacity through Britain's power links with Europe, called interconnectors, to meet demand throughout winter 2020/21.
"We expect interconnector flows to be unaffected by the end of the EU transition period ... furthermore, even in the highly unlikely event of no interconnector flows between Britain and continental Europe, we have the tools and capabilities to ensure security of supply," the grid operator said.
The so-called de-rated margin, or surplus power margin, is forecast at 4.8 gigawatts (GW), much less than the 7.8 GW forecast last winter.
The lower surplus is due to generation outages and plant closures but still within acceptable standards to ensure the system runs safely and securely and it is above levels forecast for winters 2015/16 and 2016/17.
Demand for energy on the electricity system dropped by as much as 18% earlier this year after lockdown restrictions to counter the COVID-19 pandemic but has since started to recover to normal levels.
Even if there is an increase in people working from home this winter, a reduction in commercial and office energy use should offset a demand rise, National Grid said.
Total gas demand this winter is forecast to be 50.9 billion cubic metres, comparable with last winter levels.
LNG volumes coming to Britain have increased over the past few years to 14,000 million cubic metres in 2019/20. National Grid expects volumes to be as high as that this winter as the global supply of LNG continues to exceed demand.
Domestic and European gas storage levels continue to be strong and strengthen UK security of supply in the event of high gas demand this coming winter, National Grid said.
(Reporting by Nina Chestney; Editing by David Goodman, Kirsten Donovan)
By Nina Chestney